Django序列化返回空的lis

Question

你好，伙计，我是Django的新手。我使用restapi和Django来与我的android应用程序交互。我有我在variable quest中需要的数据。因为有多个问题，我用filter代替get。在

这是我的视图.py公司名称：

class MapertablesViewSet(viewsets.ModelViewSet):
    """
    API endpoint that allows groups to be viewed or edited.
    """
    queryset = Mapertables.objects.all()
    serializer_class = MapertablesSerializer
    lookup_field = 'category_id'

    def get_queryset(self):
        #print self.kwargs['category_id']
        maps = Mapertables.objects.filter(category_id=self.kwargs['category_id'])
        #queryset = list(maps)
        #queryset =  serializers.serialize('json',maps)
        #print "AAAA ",queryset
        i = 0
        #quest ={}
        queryset = []
        queslist = []
        for question in maps:
            quest = {}
            quest['question'] = question.question_id
            #print 'qqqq  ',question.question_id
            #queryset =  serializers.serialize('json',[question,])
            choices = Choice.objects.filter(question=question.question_id)
            print choices
            #aaa = chain(question,choices)
            #print aaa
            #queryset =  serializers.serialize('json',[question,choices,])
            j = 0
            for option in choices:
                quest[j] = option.choice_text
                j += 1
            print 'data Here ',quest
            #data Here  {0: u'Highbury', 1: u'Selhurst Park', 2: u'The Dell', 3: u'Old Trafford', 'question': <Question: At which ground did Eric Cantona commit his "Kung Fu" kick ?>}
            serializer_class = CoustomeSerializer(queryset, many=True)
            print serializer_class.data
            #[]
            json = JSONRenderer().render(serializer_class.data)
            print 'JSON',json
            #[]
            i += 1

        queryset = queslist
        serializer_class = CoustomeSerializer(queryset,many=True)
        return queryset
        #print "questions",queslist
        #print "Ser ",ser.data

这是我的序列化程序.py公司名称：

^{pr2}$

定义为显示： http://127.0.0.1:8000/mapers/ 异常类型：KeyError 异常值：“类别\u id”

当我查询特定类别时，它返回： http://127.0.0.1:8000/mapers/2/ { “detail”：“未找到。” }在

在模型.py文件如下：

from django.db import models

# Create your models here.
class Category(models.Model):
    category_name = models.CharField(max_length=200,default='1')
    def __str__(self):
        return self.category_name


class Question(models.Model):
    question_text = models.CharField(max_length=200)
    #category_name = models.ForeignKey(Category)
    pub_date = models.DateTimeField('date published')
    def was_published_recently(self):
        return self.pub_date >= timezone.now() - datetime.timedelta(days=1)
    was_published_recently.admin_order_field = 'pub_date'
    was_published_recently.boolean = True
    was_published_recently.short_description = 'Published recently?'
    def __str__(self):
        return self.question_text


class Mapertables(models.Model):
    category_id = models.ForeignKey(Category)
    question_id = models.ForeignKey(Question)


class Choice(models.Model):
    question = models.ForeignKey(Question)
    choice_text = models.CharField(max_length=200)
    votes = models.IntegerField(default=0)
    def __str__(self):
        return self.choice_text

我想得到所有与类别相关的问题，这些选择形成了选择模块，为什么所有的东西都在get_queryset中。在

请告诉我如何在MapertablesViewSet类中获取所需的所有数据

提前谢谢你，如果你想让我发送完整的项目只需让我知道，我会使压缩和上传到驱动器或其他东西。在

Answer 1

您从您的get_queryset方法返回一个空列表，因此列表视图中没有返回任何对象，pk无法检索特定对象。在

您似乎在您的get_queryset方法中做了许多不相关的事情，它们可能是造成这个问题的原因。你不应该在那里做任何序列化，DRF稍后会为你处理。您应该在filter_queryset方法中进行过滤，或者将其传递给DRF来完成。您也不能从该方法返回任何响应，只能返回一个queryset。在

Answer 2

@Kevin Brown是对的，您不必担心序列化程序，或者在get_queryset方法上呈现任何内容，但是我在您的get_queryset方法中注意到的一点是，您没有向列表queryset和querylist追加任何项。我给你一个想法：

    def get_queryset(self):
        #print self.kwargs['category_id']
        maps = Mapertables.objects.filter(category_id=self.kwargs['category_id'])
        i = 0
        queryset = []
        for question in maps:
            quest = {}
            quest['question'] = question.question_id
            choices = Choice.objects.filter(question=question.question_id)
            print choices

            j = 0
            for option in choices:
                quest[j] = option.choice_text
                j += 1
            print 'data Here ',quest
            # Adding items to queryset list
            queryset.append(quest)
            i += 1

        # You should have values here on queryset list
        print queryset

        return queryset

至于URL，请确保将category_id作为URL模式的参数传递。类似于url(r'^mapers/(?P<category_id>\d+)/?'，如果您没有使用routers来完成此操作。如果你把你的网址定义粘贴在这里就好了。好吧，我希望它能帮助你更好地了解如何继续下去。在